[pianotech] WNG jack don't come back no more, no more, no more.....

[Nicholas Gravagne]

On Thu, Jan 19, 2012 at 11:18 AM, Encore Pianos
<encorepianos at metrocast.net>wrote:


> .....
>
Readers, Nick and I had a phone conversation about these parts about a year
> and a half ago, where we shared our observations and solutions.  Nick, did
> you end up repining the rep lever posts to a higher gram resistance
> reading?
>

Yes, but not all of them (long story). Repining the lever posts made a
noticeable improvement, but in my case I did not drill out / remove a cloth
"pin" as you did, but rather had to drill out the small "plastic" pin then
bush and pin the hole. The coil of the spring now fit snugly over the new
cloth and pin This anchored the spring and added a secure stability to both
free ends of the spring. No slippage.

****
>
> ** **
>
> I am in agreement with your observation about the zone of adjustment
> acceptability being narrower than with wooden parts, although I would say
> that it likely has less to do with wood than other design considerations.
>

Yes.


> The zone of adjustment acceptability in general is narrow with these
> parts.  Within those parameters, the parts can function quite well, outside
> that you start to have problems.  Other good techs whom I know who have
> used these parts also have come to this conclusion.
>

Yes.


> ****
>
> ** **
>
> It is interesting to hear about the success of your shortening of the rep
> lever half of the top spring, I knew you were planning on doing this but
> did not know how it worked out.
>

It definitely helped in both performance and regulation-ability. But the
bend in the rep spring half (either before of after shortening) is not as
pronounced as in wood parts, being rather flat. This made tool use a bit
less comfortable. But all in all the bushed post and shorter top spring
made a noticeable and positive difference. A lighter gage wire would help
by at least allowing for a more pronounced and graceful upper bend as well
as open up the zone of adjustment acceptability and improved tool feel, but
would not necessarily kick the jack in the butt (couldn't resist:) with any
more power.


>  If I had thought to do this back then, I would have done this at the same
> time I had the springs out to increase the size of the barrel.  While I do
> not have the direct experience of success that Nick has, I had my head
> buried long enough with the problems with these springs to believe that
> this is worth doing.
>

Yes, though I wonder if replacing the springs with lighter gage all around
(supply house springs?) would be a good idea rather than fighting with that
"piano wire" spring.


> ****
>
> For Ed Foote, I would make all my decisions about what modifications may
> be necessary to improve and optimize the performance of these parts and
> take the whips off the rails once and do them all at the same time.  It’s a
> lot less time doing them all at once, than finding out you need to do each
> thing, one at a time.  I spent a lot more time going backwards before I
> could go forward.
>

Same here. I tried repining the jack; bought the expensive repining kit
(comes with instructions). This kit is not what we are used to and the
procedures are tricky, though with practice I'm sure a modicum of
proficiency would be had. The "pins" are needle bearing (nice idea) and the
increments change almost microscopically.

So, as to the sluggish jacks. I would check the interface of the spring
insertion into the back of the jack activating hole. Is the engagement
length a bit too long. Is the angle of the entrance of the lower spring as
it approaches the jack heel to shallow or too steep. If too shallow bend it
to a more pronounced curve and readjust the spring for hammer rise. WNG and
Bruce Clark have a spec for jack grams movement; you may have to bend the
rules and pin it with less friction. This would mean, of course, gaining a
proficiency in the one task of removing all jack pins and repining same.
Try one, say note 88, and see what happens.

Nick

> ****
>
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>  ****
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> *From:* pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] *On
> Behalf Of *Nicholas Gravagne
> *Sent:* Thursday, January 19, 2012 11:50 AM
>
> *To:* pianotech at ptg.org
> *Subject:* Re: [pianotech] WNG jack don't come back no more, no more, no
> more.....****
>
> ** **
>
> ** **
>
> On Thu, Jan 19, 2012 at 8:44 AM, Encore Pianos <encorepianos at metrocast.net>
> wrote:
>
> Will writes:****
>
> Combine the too heavy gauge of wire for the hammers with rep springs where
> the coil flops around on a too small barrel (.050 difference) along with a
> jack top that is visibly smaller in width and length than other comparable
> grand jacks (the WNG jack is, and that means that the top of the jack is
> carrying a much higher load than a comparable jack, ****
>
>
> Will -- a bit of nitpicking here, but the load has not changed; what has
> changed is the intensity of the force (higher) and friction owing to the
> smaller carrying surface area of the jack top. Your argument still
> theoretically holds, however.
>
> ... ****
>
> My solution to these too heavy guage rep springs was to repin the rep
> lever posts at about 10 grams to slow the karate chop kicks of the hammer
> from the springs so that you would get a much slower and controlled rise.
> The too heavy springs make the adjustments hypersensitive and a giant pain
> in the ass to regulate.  ****
>
>
> Whether the rep spring wire gage is heavy or lighter, the same force from
> either will be required to raise the hammer in the manner that most of us
> agree on and with a concomitant and beneficial effect to the jack behavior
> as well. "Too heavy" a gage, as I recall with my set, behaves exactly as
> you say, making the "adjustments hypersensitive...". I recall that the zone
> of adjustment acceptability was much narrower than we are used to with
> traditional wood parts.****
>
>  ****
>
> By the way, all this was on an early set of cloth bushed WNG parts made 2
> years or more ago.  I suspect that in Ed Foote's case, some of these issues
> may remain while others may have been addressed, as I had long
> conversations with Bruce Clark about these issues some time ago.  ****
>
> Likewise. It was my understanding that a lighter gage wire was being
> considered. In my experiments with the rep lever half of the spring ----- I
> shortened this segment and re-curled the top with rounding pliers keeping
> the curl well within the rep slot. This shortened segment had to now work
> harder to lift the hammer yet left a reasonable amount of tension in the
> jack segment. BTW, my parts were all hard bushed.
>
> NG
>  ****
>
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-- 
Nick Gravagne, RPT
AST Mechanical Engineering
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